POS0736 SYSTOLE AND DIASTOLE ULTRASOUND WALL THICKNESS SHOWS SIGNIFICANT DIFFERENCES THAT AFFECT THE DIAGNOSIS AND ASSESSMENT OF GIANT CELL ARTERITIS
Authors: E. Brugarolas Martinez, E. Fernández-Fernández, I. Monjo, M. D. C. Uyaguari Morocho, E. De Miguel
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> In the last few years, several cut-off points for the intima-media thickness (IMT) of temporal arteries (TA) and large vessels (LV) have been proposed for the ultrasound (US) diagnosis of giant cell arteritis (GCA). It has usually been recommended to use the average measure of the higher IMT, but there is currently a lack of consensus on this. We have observed some changes in the IMT measurements depending of if they are performed in systole or diastole. <h3>Objectives</h3> The main objective of this study is to confirm if there are differences in the IMT measurement taken in systole or diastole and if they are clinically relevant. <h3>Methods</h3> Observational retrospective study on consecutive patients of our GCA fast track clinic. The gold standard diagnosis was the opinion of the clinical doctor after at least 6 months of follow-up. US recorded videos, of every explored vessel temporal (common trunk, frontal and parietal branches), subclavian and axillary arteries were reviewed and the IMT of each of them was measured in systole and diastole peaks for comparison. We define an ultrasound result as positive with cut-off values of IMT ≥ 0.34 mm for frontal and parietal branches, ≥ 0.42 mm for the common trunks of TA, and ≥ 1 mm for the axillary and subclavian arteries. Demographic data of the included patients were also collected. <h3>Results</h3> We have included 72 cases, 36 with GCA diagnosis and 36 without GCA (controls). The mean values of age and sex, as well as the IMT in systole and diastole of each vessel are shown in Table 1. There were not significant differences in sex but patients without GCA were younger (p&lt;0.01). The US IMT measurements at the systolic and diastolic times showed statistically significant differences in all the explored vessels, as in patients with GCA as in the control non GCA group. All the IMT measured in diastole showed higher and statistically significant values than those measured in systole, with a mean increment of measurement of 5.3% and 6.5% in TA and 6.4% and 5.6% in LV, respectively in the GCA and control group. This result can be of clinical relevance because if we used diastolic measures, instead of systolic measures, 5/36 (13.8%) cases in controls had halo sign in one isolated vessel (2 cases in parietal right, 1 in common trunk right, 1 in subclavian right, 1 in subclavian left). However, in GCA patients, the number of patients with halo sign did not change, but the number of pathological vessels was increased when the measured was performed in diastole (1 frontal right branch, 1 common trunk right, 4 frontal left branches, 5 common trunks left and 2 axillary right), so this could have influence in the assessment of the disease. <h3>Conclusion</h3> There are significant differences between the IMT measured in systolic and diastolic peaks, with higher values in diastole. The differences are relatively small but may increase the number of false positives (13.8%) in controls, and the number of affected vessels in the GCA group. This should be considered in the diagnosis and assessment of GCA. <h3>REFERENCES:</h3> NIL. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.